AUA 2019: PSMA Uptake on 68Ga-PSMA-11-PET/CT Positively Corrects with Prostate Cancer Aggressiveness
In this study, the authors from China examine the relationship between PSMA/PET CT standardized uptake values (SUVs) with features of prostate cancer clinical aggressiveness – specifically Gleason score, T stage, initial PSA and tumor size. As this required a comparison to histopathology, all 51 patients in this study were retrospectively assessed.
They retrospectively reviewed 51 patients who had underwent 68Ga-PSMA PET/CT (PET/CT) before radical prostatectomy (RP) as a staging study. PET/CT results were then correlated with whole mount histology, and the relationship between SUVs and aggressiveness was analyzed. The cutoff value of SUV for detection of overall PCa, csPCa (as defined by the prior criteria) and intermediate/high-risk PCa were calculated by receiver operating characteristics (ROC) analysis. They looked at both SUV-max and SUV-mean.
On univariate analysis, they found that both SUVmax and SUVmean were positively correlated with Gleason score (SUVmax Spearman r=0.546 p<0.01, SUVmean Spearman r=0.359 p<0.01), PSA level (SUVmax Spearman r=0.568 p<0.01, SUVmean Spearman r=0.529 p<0.01) and tumor volume (SUVmax Spearman r=0.635 p<0.01, SUVmean Spearman r=0.590 p<0.01).
Tumors with pT3 disease had significant higher SUV uptake than those with pT2 (SUVmax 17.49 ± 10.50 vs 9.90 ± 8.7, p<0.01; SUVmean 17.49 ± 10.50 vs 9.90 ± 8.7, p<0.01). On ROC analysis, they found that a cutoff of 3.8 (SUVmax) and 2.8 (SUVmean) had the best predictive ability for overall PCa detection. However, for identification of csPCa and intermediate/high risk PCa, the cutoffs were 8.4 (SUVmax) and 6.8 (SUVmean).
As can be expected, patients with higher grade disease or more aggressive disease had higher SUV than those with more indolent disease. This information is important in helping to develop guidelines for how to interpret these PSMA/PET CT’s, as they become more popular.
Presented by: Mengxia Chen, Department of Urology, Drum Tower Hospital, Medical School of Nanjing University, China
Co-authors: Xuefeng Qiu, Qing Zhang, Chengwei zhang, Yihua Zhou, Xiaozhi Zhao, Yao Fu, Feng Wang, Hongqian Guo, China
Written by: Thenappan Chandrasekar, MD (Clinical Instructor, Thomas Jefferson University) (twitter: @tchandra_uromd, @JEFFUrology) at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois